The present invention relates to a lens for use with light-emitting diode (LED) light sources, for example, light fixtures and lamps such as free standing lamps, stop/tail/turn lamps for vehicles, etc. More particularly, the present invention relates to a lens having a structure suitable for maintaining or magnifying the intensity of light emitted from the LED as well as to facilitate dispersing the emitted light.
One of the problems associated with using a light-emitting diode (LED) light source, for example, in a lamp for a vehicle, is the difficulty in spreading the illumination in a longitudinal direction, i.e., an arc-like pattern. While LEDs are often preferred because they can have an operating life of up to 100,000 hours before degradation commences, the light emitted from LEDs is in a narrow cone-shaped pattern. More specifically, an LED is a directional light source in which light is emitted in a direction generally perpendicular from the light source. The amount of longitudinal dispersion is minor compared to an incandescent bulb. A typical radiation pattern for an LED is within approximately 20° of the direction generally perpendicular from the light source. Therefore, LED lamps or light fixtures may be insufficient for adequately illuminating an area, such as a room, a hallway, an outdoor area, etc.
Vehicles, such as an automobile or truck/trailer combination typically have stop/tail/turn lamps on the front and/or the rear of the vehicle, to indicate that the vehicle is stopping, turning, changing lanes, etc. The stop/tail/turn lamps typically include a housing, which includes the light source, and a lens, which protects the light source from the natural elements. Typically, the light source is either a standard high-intensity incandescent bulb, which has a relatively short life span and is susceptible to damage, or an LED, which has a greater operating life. However, the narrowness of the emitted light can render LEDs less than completely satisfactory for use in stop/tail/turn lamps.
Thus, there exists a need to provide a lens suitable for use with an LED light source, such as a lamp, a light fixture, stop/tail/turn lamp, etc. which is relatively inexpensive and easy to manufacture and which in combination with the LED can provide sufficient illumination, for example for use on a vehicle.